The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
A transmission, particularly a hydraulically controlled planetary gear automatic transmission for a motor vehicle, operates at temperatures well above ambient, often at 130° C. (265° F.) or higher. Because the transmission may begin operation at ambient temperatures as low as −35° C. (−30° F.) or lower, the air within the transmission will undergo significant expansion. Conversely, when the transmission becomes inactive, the transmission's nominal temperature may drop relatively rapidly and the air within the transmission will contract. In order to accommodate these changes and to avoid pressurization or a partial vacuum within the transmission, a transmission is equipped with a breather system which allows exhaust and ingestion of air. Under extreme conditions, fluid could also be expelled from the transmission.
Some transmission breather systems include a vent cap and a hose extending from the vent cap. The vent cap may be installed onto a top side of the transmission case, and the hose may then extend upwardly from the vent cap. Such a configuration allows installing, or screwing on, of the vent cap in any orientation. This configuration requires space for the hose to be located above the vent cap and transmission. Reduced packaging needs and smaller components, however, are a constant goal in transmission design.